I just wanna gripe about my evolution .61 I have,and likely the last evo I'll own. This thing has 2 BAD problems that even the best r/c guy at my field cant figure out.

1: During long inverted climbs it dies every time......It seems to lean itself out and quit during this maneuver. It helps to richen the motor a tad too much,but it really takes away from the overall power,plus it still dies....just takes longer. We've tried about everything including putting fuel line piece around the needle valve to seal it up from any air leaks. I just sure seems to lean itself out because it gets alot worse as the tank gets lower and lower. It runs fine everywhere else,just hates long inverted climbs.

2: The transition from idle to full throttle is HORRIBLE......It either dies from being too lean on the low end or spits and sputters like crap until the high speed needle takes over. No in between. This makes taking off more difficult as you throttle up. And you better not botch your landing and have to "punch" it.

On a side note....this engine above all my others is WAY more affected by heat and humidity.


I've been flying this engine in my sukhoi for awhile now and it bugs the crap out of me every time. It runs.......just not real well. It a very UNpredictable tune. I've grown used to it,but will never like it.

The only thing good I can say about it is that its the coolest LOOKING engine I own,lol.

Check your tank height in relation to the SPRAYBAR in the carb and make sure the clunk is free moving in the tank. The tank/spraybar height is most likely the reason the engine dies out on you while inverted. When engines are inverted (or the plane is flying inverted) the tank height becomes critical to proper running.

As for your transition problem,

1. Make sure the fuel is fresh.

2. Try an OS #8 plug. If that doesn't help, try an OS #A3 plug. You will most likely need to adjust your low end/high end after the plug change.

Fresh fuel AND the proper heat range plug can improve 98% of transition problems.

Hope this helps.

that really stinks man.. i have a evo .46 that has been through more than i ever could have expected.. it came with my hobbico superstar when i first was learning to fly and i crashed that plane a total of 13 times with repairs and then stuck it on a spad that i never could get balanced out properly so i finally drove it in to pavement and then once on my new h9 cessna it went straight in when my stupid L bend didnt hold on the elevator servo, it popped loose and the plane went straight in at high speeds.. each time i took a blow gun hooked to a compressor and just blew it off and the carb out and repaired the plane and slapped it back on there and dogged the crap out of it with 15% nitro.. so i have had an amazing experience with evolution so sorry for your bad experience, has this been the only evo engine you have owned? if so i might give evo another go or maybe contact them and see what they would charge to check it out, quite possibly they will find something defective and fix or replace it! i urge you to send it in man, give it a shot!

TRY REMOVEING THE REMOTE NEEDLE VALVE AND MAKING IT A STANDARD JUST REMOVE THE PLUG FROM THE CARB AND MOVE THE NEEDLE VAVLE ASSENBLY TO THE CARB THAT FIXED MY EVO 100. JEFF IN WINSLOW

im sure that if you have been having this problem a while you have tried replacing the plug but if not that would also be something to try, after that just completely change the fuel tank to one of your other plane's tanks that you know works if you have it mounted in the correct spot and none of that corrects the problem then send her in and tell evolution what it is doing and what you have done to try and remedy the situation and most likely they wont charge you for repair or replacement!

TRY REMOVEING THE REMOTE NEEDLE VALVE AND MAKING IT A STANDARD JUST REMOVE THE PLUG FROM THE CARB AND MOVE THE NEEDLE VAVLE ASSENBLY TO THE CARB THAT FIXED MY EVO 100. JEFF IN WINSLOW

I have to agree with Campy,
Sounds more like a tank problem rather than engine as far as the engine dieing when climbing inverted.I guess it could be a bad glow plug too.
Can't help with the idle aside from the usual, ie.. change glow plug, make sure carb is seated properly and O ring in good shape.

Is the outlet line from the tank within about 3/8" or 1/4" of horizontal to the carb inlet fitting ahen the model is level? If more than that the muffler pressure will have a hard time pushing the fuel into the carb when inverted - causing a lean run.

IMHE engines don't care what position they are in. I run them upright, tipped 90º and upside down. The problem is in the fuel system 80% of the time - either air intrusion or fuel delivery.

If the tank has conventional clunk venting with the vent stuffed at the top of the tank, when its inverted it'll act like a uniflow when that one vent is covered with fuel -- IOW, the engine has to suck harder because an equal amount of air needs to get sucked in through the vent to match the fuel going to the engine and has to overcome some depth of fuel to do so. This would naturally cause the engine to go lean compared to upright when the vent is not immersed in fuel freely allowing air in the tank

That it helps to richen it up leads me to believe this is the situation you have.

Whompie - please turn off the caps lock.

I agree that it sounds like a tank issue - either position or possibly an air leak someplace. I went through this with my Sky Raider - it got to the point that if I did a slow roll the engine would quit. After I changed the tank the engine quitting issues stopped, but I think the damage was done from going just lean enough in flight that it couldn't be heard as the ring has blown out [&o].

I have an Evolution .61 and it starts right up and hasn't missed a beat. I've converted it over to a 2-blade 12 X 6 prop and have to tweak the low-end which is a bit on the fat side form the 3- blade. It is a new engine, but so far I haven't had any issues with it, and it now has close to 1 gallon through it. No matter what position ot throttle setting the plane is put into, it has not shown any sign of giving any problems.

Hogflyer

I had three of them [:@] .46, .61 and 1.00. All were, well, let's say I don't have them any more. The 1.00 was so unreliable that as long as I had it on my Excelleron 90, that plane never.. NEVER consumed a full tank of fuel. I replaced it with an OS 1.20 AX and never looked back. I was so glad to get rid of those engines.

The problem I had was very similar to what you are experiencing with your .61. I just got fed up and, well, no sense rehashing that. I even had the 'club pro' looking at the thing and, every time he said it was good to go, it would fail. He even threw up his arms in disgust and suggested I move over to OS, which I did. Same setup (tank position, fuel feed, everything) and it (the OS) ran like a charm right out of the box.

CGr

Are you sure it is actually leaning out? I have an Evolution .45 that did the same thing but on the ground I found that it was actually getting too much fuel. What made me think it was too lean was that when it stopped in flight the fuel line was empty, but what was happening was that the fuel was just siphoning back into the tank before I got to the plane to look at it.

The engine still ran like crap though until this past weekend. I put a GMS muffler on it and it ran better than it ever had. It transitions beautifully now as well.

By the way, I have an Evolution .36 that as ran perfectly from day one, and a buddy got a .36 in which the head gasket wasn't but on correctly and leaked until he got new gaskets to install. The quality seems to be real hit and miss. Another flyer at our club has a .46 that has run fine from day one.

Is the muffler exhaust pipe pointing up? if it is there might be some accumulation of spent oil in the muffler's chamber. This might cause this oil to clog (oil is surely harder to push than air) or return to the fuel tank through the vent pipe when you are flying inverted. If the carb is setup correctly and you haven't found any air leaks in the high speed needle assemble then replace the tank.

My two cents worth - sounds like a fuel delivery problem:

1. try a header tank - a small 2 oz. tank between the main tank and engine. It always stays full

2. try a double clunk tank set up like the CL guys use. You won't beleive the boost in pressure it gives - sometimes too much. Not sure where you'll find a diagram. You could search this forum.

That's a uniflow clunk setup. It doesn't provide "more pressure" per se, rather it works to equalize the pressure within the tank at various attitudes because vent air bubbles are always being drawn through fuel and what comes in always equals what goes out. Initial needle settings on a uniflow will typically have to be set a few turn richer than on conventional venting.

Uniflow will give very consistent runs until the fuel is almost completely spent. I don't know why more people don't use it. Maybe they don't understand it.

The dual tank setup may also cut down on fuel foaming due to vibration, if the second tank is mounted properly. Good idea, guys.

Had the exact same problem with a Saito .82 on a Venture 60. Played around with both needles (hi,low) with no success. Really didn't want to get into the tank, because it is quite a chore to get it out and back into the plane. Finally had to do it. I shortened the fuel line in the tank to give the clunk more space away from the back of the tank (about 3/4 inch). Apparently, the clunk was too close and while climbing for extended periods the fuel line would stretch just enough causing the clunk to basically suck up against the back of the tank preventing proper fuel flow. Haven't had the same issue since. I had it set up so I could get every last drop out of the tank, but I've decided that's not practical.

I'm interesting in seeing one of these. Anyone have any pictures?

I had a finicky Evo 61 that would change settings in the air. I replaced the carb with an TH 75 as an experiment and now it runs reliable but only average power. I won't buy another one. In this size range I only buy TH 75 engines now! [8D]

IMHO Uniflow is a bit overly complicated. On .40 & .60 size I just use two lines and attach the vent line to the muffler pressure line. Solves the problem by pressurizing the tank.

I've had great luck with the PTS ( .445 ), the .46 and .61 engines...

The 1.00Nx was HORRIBLE! Never again will I buy one of these.

I had one in my Funtana 90S, which spent more time deadsticking than flying. I think my takeoff to deadstick landings ratio was something akin to 1:1.

Hey! I had an S/K .50 engine that ran like that. After much futzing and consulting the glow guru at my club we decided it was sucking air from multiple locations and I retired it. I believe my record was 15 dead sticks in a single day without a single completed Vertical Cuban Eight (my engine test pattern). Learned me that when the price seems too good to be true ($47.77 intro!) it may be too good to be true. Replaced it with a ST G-51 and never looked back.

Like their ARFs though.

Oddly enough, I had a Pranger (foam with packing tape for adhesive and a pine spar.. ) when working in England about three summers ago. It had an EVO 46, not the trainer version, but the .46 version. I believe their trainer is 40 size. Anyway, doen't matter. The .46 ran just fine over there, but after I brough it back here and put it on a Goldberg Wildstick 40, it ran like crap, would not stay running, all the same symptoms as I had with the 100. That really confused me because we really put it through the wringer in England, and it ran fine with plenty of power. That 100, when it ran, seemed that it would do fine, but it was a POS. It would deadstick shortly after leveling out after my initial takeoff-turn to downwind forcing a deadstick landing.

We played with that thing until we were blue in the face with no success. We were going to put a $90.00 OS carb on board, but I figured for what it cost me total (engine plus carb), I could almost buy an OS 1.20 AX which I did. The EVO 100 is still on consignment at the LHS. No one wants that POS and I can't blame them.

CGr.

I've been playing around with a Perry carb. This is on a twice-crashed Thunder Tiger Pro-46 (last crash sheared off the needle valve housing). I can't believe the range this carb has in the rich region. I swear I can ritchen it up until it looks like a little toilet flushing at full throttle, four-stroking and slobbering, and it still runs the engine!!! The idle settings are a little finiky ("a few thousandth of an inch") but once set it's hands off thereafter. Now why can't engine makers use this system? (I guess Fox come with Perrys, or maybe it was another brand?).

I have my little TT46 pushing a 11X5 prop at 13,600 rpm (I richen it to 13,300 by my little tach) with 10% nitro.

Anyway, it may be worth a try swapping out the carbs on these lemons for a Perry. They come in dozens of sizes. I would hesitate to throw good money after bad but hey, this is R/C and that's the nature of the sport. They cost around $40

You knew this was going to happen when you made this comment in another thread-(I'm gonna make an evolution .61 post,lol. )
This is the usual Ford, Chevy, Dodge discussion. I had a ford once it never ran right , I will never get another one, I had a Chevy once & that thing fell apart in 6 months, I will never get another one, I had a Dodge once it didn't have enough power to untrack itself, I will never get another one. This is the same old discussion. Bottom line is we have all had a bad something or another at some time. sometimes you get a good one sometimes you don't. Over the years I have had just about every kind of 2 stroke made, OS - some good & some bad, K&B - some good & some bad, Fox - some Good & some bad, HB - some good some bad, MDS - some good some bad, Evolution (well I haven't had a bad one yet but im sure i will). If one company made the best engine out there that never broke, never stopped running in flight, you never had to change it's settings because of outside temp, never lost a bearing, never wore out then we wouldn't have much choice in engines because everyone would be buying the same one. Good Grief.

Wow,thats alot of responses fast! I'll give you some more of my info and stuff for whatever its worth. Lets see,my engine is mounting horizontally. It should be plenty fine as far as the main needles position to the tank etc. My exhaust point down. I believe some are thinking when I said "inverted" that my problem was when the plane flys upsidedown. I actually mean "inverted" as in the plane is going straight up vertical(sry for the poor use of inverted). I always make VERY sure my clunk is far clear of the back of the tank. Umm....that one guy said it could come from the exhaust not having enough pressure to vent the tank. This made me think a bit,but it cant be that because the problem gets progressively worse as the tank gets empty. If it were a vent issue,it seems that it would get better as the tank got lower I think. I've tried shortening the fuel lines and that didnt help. The only thing I can think of is I believe the fuel line inside the tank is a narrower type. I woudnt think this would be a problem,but you never know. I just dont want to rip the tank apart till I need to tear everything apart again. I did try different plugs too,and has an OS in it now. The ideas of a second tank COULD help and whatnot,but I'd sell this strange engine and buy something else before I'd go through all that hastle. That kinda my grudge against this EVO.....I shouldnt have to go through all this to get it to run good,know what I mean? I'm not saying all EVO's are bad,but I just dont care for mine. I might get it running great someday,but I'll still not buy another anytime soon. The plane and the way the engine is installed are about as simple and textbook as you can get as are all my planes,and this EVO is the only one I havent got running like a top. It just doesnt seem "user friendly",lol.